Shoring jack



Oct. 5, 1965 G. w. JACKSON SHORING JACK Filed June 1v, 196s a 5 6 ma I n 3 l .l v Q@ 7 6 5 4 United States Patent O 3,210,047 SHORING JACK George Wilbert Jackson, 1848 W. 1st Ave., Vancouver 9, British Columbia, Canada Filed June 17, 1963, Ser. No. 288,155 6 Claims. (Cl. 2'54-98) This invention relates to jacks, having particular reference to a shoring jack where a short lift is required.

In the shoring of concrete slabs the length of the shore may vary from as little as six feet to various lengths. The present device is concerned with meeting shoring requirements from six to ten feet, or from ten to fifteen feet, the lift not necessarily being limited to these lengths..

For this the shoring jack as herein disclosed is designed for use for any purpose where considerable takeup adjustment may =be required, as in shoring concrete floors or slabs in building, or in ditch shoring.

The jack includes a load engaging element in the form of a tube mounted freely endwise movable in a standard on which is concentrically mounted an outer casing. The tube is automatically engageable by spring urged locking jaws carried by the outer casing to hold the tube in load engaging position, and these jaws are disengageable from the tube by retraction of the outer casing on the standard. For this, in the present showing, the outer casing is in threaded engagement with the standard and the standard aligns with the jaws by which downward movement of the outer casing on the standard brings the upper end of the standard against the lower ends of the locking jaws for effecting disengagement of the jaws from the tube.

Other features and advantages of the invention will become apparent by reference to the accompanying description taken in conjunction with the drawings.

In the drawings, wherein is illustrated a preferred ernbodiment of the invention,

FIG. 1 is a side perspective view, partly in vertical section and broken away, of a jack embodying my improvements shown with the load engaging tube as it would be when engaging a load.

FIG. 2 is a perspective view of the jack complete, shown with the load engaging tube partly extended, and as it would be when engaging a load.

FIG. 3 is a top plan view of the jaws and cup ring.

Having reference to the drawings, the jack includes a tubular base standard 1 to 4be threadably mounted in a collar 2 of `a base plate 2 (FIG. 2). This mounting permits extending the standard by attaching a length of pipe 1 to the standard by a coupling 1", the length of pipe threading in the collar 2. On the standard 1 is threadably mounted a cylindrical outer casing 3.

The endwise upward movement of the casing on the standard is limited by an internal retaining ring 4 inset in the casing at 5, and which engages against a split stop ring 6 on the standard. The downward movement of the casing on the standard is limited by an external retaining ring 7 set in the standard engageable with an annular shoulder 8 in the outer casing.

The threaded engagement between the outer casing and the standard is by a machine thread and the relative movement of these is limited by the retaining rings, about three inches being a suicient movement, but this could be increased as desired. Within the standard 1 is mounted, freely movable therein, a load engaging tube 9 frictionally engageable by a set of jaws lll, preferably three. These jaws are tapered inward on their outer faces 11 complementary to a tapered inner face 12 of a jaw retaining cup ring 13 that is inset in an annular recess formed in the outer casing 3.

The jaws and cup ring 13 are held seated in the recess 14 by a retaining cap 15, the cap having an annular 3,210,047 Patented Oct. 5, 1965 recess 16 in its under side in which is engaged a spring 17 in the form of a spiral coil that bears against the upper ends of the jaws. The cap includes an annular depending portion 15' terminating slightly above the upper end of the cup ring 13, which allows the casing 3 to turn without turning the standard 1 or tube 9, the casing recess 14 forming a bearing surface for the cup ring. A set screw 18 holds the cap 15 in the casing, and the cap has an outward slope downward on its upper side which helps keep the dirt and water out.

The jaw sections 10 have serrated inner faces 19 for a better frictional engagement of the tube 9, `and the spring 17 normally holds the jaws in clamping engagement with the tube, the jaws being pressed inward by the wedging action of the tapered contacting faces of the jaws and cup ring.

For turning the casing 3 on the standard 1 a handle 20 is provided pivoted on a pin 21 in lugs 22 lon the side of the casing, the handle bearing against a spring 23 mounted at its upper end at 24 inset in the casing and with the center of the spring bearing against the handle to hold the handle in either a horizontal or a depending position.

On the top of the tube 9 is a load engaging head plate 25 that can be changed for any desired shape for different types of work. An opening at 27 permits greasing the cup ring and jaws without dismantling the jack.

In the use ofthe jack, the jaws 10 normally tighten automatically on the tube 9, the jaws being urged downward by the spring 17, this securing the tube 9 to the casing 3. To loosen the grip of the jaws on the tube 9 the handle 20 is used to turn the casing 3 clockwise on the standard 1, and through the threaded engagement of the casing and the standard the casing moves downward on the standard bringing the lower ends of the jaws against the upper end of the standard. Continued movement of the casing downward pushes the jaws upward in relation to the ring 13 and releases the tube 9 so that it may move freely in the jaws. A reverse movement of the casing 3 releases the jaws and they are then pushed downward by the spring 17 and engage the tube again. To set the tube 9 in load engaging position a partial turn of the casing 3 is sufficient to secure the jaws on the tube 9 and allow it to be moved in a jacking motion for the length of the thread to be stopped Aby the split rings 6 and 7.

What I claim is:

1. In a shoring jack, a tubular standard, a load engaging element mounted free to move endwise in the standard, an outer casing threadably mounted on the standard for endwise movement thereon, a cup ring in and supported by the upper end of the casing, jaws mounted in the cup ring engageable with the load engaging element, said jaws and cup ring having complementary tapered opposing faces by which downward movement of the jaws in the cup ring forces the jaws inward into engaging relation with the load engaging element, said standard having the upper end thereof in 4opposing relation to the lower ends lof the jaws by which a downward movement of the casing on the standard causes the upper end of the standard to push the jaws upward out of engaging relation with the load engaging element.

2. A shoring jack as set out in claim 1 and in which the jaws are frictionally engageable with the load engaging element.

3. A shoring jack as set out in claim 1 and including spring means in the outer casing bearing down against the jaws for automatically effecting engagement of the jaws with the load engaging element.

4. In a shorting jack a load engaging tube, a tubular standard in which the tube is mounted free to move endwise therein, an outer casing threaded on the standard for movement endwise thereon, a cup ring in the outer casing, an annular set of jaws mounted in the cup ring, said jaws and cup ring having tapered opposing faces by which a downward compression movement of the jaws in the cup ring urges the jaws inward to frictionally engage the load engaging tube, and spring means carried by the casing normally pressing the jaws downward, said standard having its upper end in opposing relation to the lower end of the jaws, by which downward movement of the casing on the standard may cause the jaws to be pushed upward thereby to release the load engaging tube.

5. A shoring jack as set out in claim 4 and including stop means in the outer casing and standard limiting the relative endwise movement of the casing and standard.

6. A shoring jack as set out in claim 4 and in which the outer casing is formed with an annular recess in which the cup ring is seated, said recess forming a bearing for the cup ring permitting the outer casing to turn relative References Cited by the Examiner UNITED STATES PATENTS 2,045,927 6/ 3 6 Ritter 254-98 2,777,660 l/ 5 7 Albrecht. 2,834,081 5/58 Stump 24h-263.5

WILLAM FELDMAN, Primary Examiner.

MILTON S. MEHR, Examnen 

1. IN A SHORING JACK, A TUBULAR STANTARD, A LOAD ENGAGING ELEMENT MOUNTED FREE TO MOVE ENDWISE IN THE STANTARD, AN OUTER CASING THREADABLY MOUNTED ON THE STANDARD FOR ENDWISE MOVEMENT THEREON, A CUP RING IN AND SUPPORTED BY THE UPPER END OF THE CASING, JAWS MOUNTED IN THE CUP RING ENGAGEABLE WITH THE LOAD ENGAGING ELEMENT, SAID JAWS AND CUP RING HAVING COMPLEMENTARY TAPERED OPPOSING FACES BY WHICH DOWNWARD MOVEMENT OF THE JAWS IN THE CUP RING FORCES THE JAWS INWARD INTO ENGAGING RELATION WITH THE LOAD ENGAGING ELEMENT, SAID STANDARD HAVING THE UPPER END THEREOF IN OPPOSING RELATION TO THE LOWER ENDS OF THE JAWS BY WHICH A DOWNWARD MOVEMENT OF THE CASING ON THE STANDARD CAUSES THE UPPER END OF THE STANDARD TO PUSH THE JAWS UPWARD OUT OF ENGAGING RELATION WITH THE LOAD ENGAGING ELEMENT. 